Peptide Mass Fingerprinting

Practice: Peptide mass fingerprinting (PMF) is a method used to determine the sequence of an unknown peptide. In the sequencing of peptides by PMF, tandem mass spectrometry fragments peptides into smaller molecules to obtain the mass spectrum, which acts like a fingerprint & can be compared to theoretical spectrums in a database to derive the amino acid sequence. Mainly which types of bonds are broken to fragment the peptide & generate tandem mass spectra data?

Practice: Explain how a 5-residue amino acid sequence could uniquely identify a 200-residue protein via PMF. 

Hint #1: Compare the number of pentapeptides in the 200-residue protein to the total number of all possible pentapeptide sequences.

Hint #2: 

Hint #3: